Dynamic Verification of the Effects of Varying the Inclination of the Inertia and Roll Axis in an Automobile

The aim of the present study is to identify the effects produced by varying the inclination of the longitudinal inertia axis and the roll axis on the dynamics of an automobile. The objective is to find technically valid solutions to the optimisation of the vehicle in order to improve its handling behaviour and safety. Selected one of the cars available on the market, the ADAMS calculation code was used to create a multibody model of the car reproducing its dynamic behaviour. The model simulates in detail all the vehicle, including engine, front and rear suspension, brakes, steering line and tires. The experimental validation of the numerical model was performed comparing the analytical data with those measured at the Flat-Trac Roadway Simulator on a real vehicle in road configuration. Creating appropriate Design variables and using the Design study technique, it was possible to parameterise the geometry of the model in order to study the influence of the above axes on handling behaviour. In order to better understand the phenomenon, mainly the effects on the slip of rear axle, it was also created a model with a simplier architecture of the rear suspension. It has allowed the analysis of the influence on the tires of the vertical load transfer providing also a physic verification of the results. On the basis of the simulation analysis, design suggestions have been made for further vehicle improvement.